Can someone explain this one for me?

I don't mean to be a pest on this list, but this is more than just a
little confusing...

Why is it, that I cannot mount via nfs an export from another system on
my network IF I also happen to be running my pmax as an nfs server?

When I try, mountd says something about "filesystems disagree"...what the
devil does this mean?  It seems to suggest that I must also be exporting
the same filesystems because it does mention those I've identified in the
/etc/exports file...but what does that have to do with mounting an 
exported
filesystem from another machine?

The only way I could do it was to kill off the server processes...then it
worked just fine..

??
Paul